Deaerator



Mm m Kw s. ROWN 1,3,3

nmmmon I Filed Nov.'l9,- 1926 4 Sheets-Sheet 5 i-HS JATTORNEYS.

March 11, 1939 5 BROWN I DEAERATO'R Filed Nov. 19, 1926 4 Sheets-Sheet 47 0 BOILER TURBINE ll eitented ll/llart llll, lltlhltl I renown, orcrrr, HEW roar-t, nestle-non, 'ro enrsoora iaussnrrt tlt'dlEtPtlEtlTlUllon .tlpplteationtlled lto eniher it),

, tains certain amounts of dissolved gases, such for example as oxygen,carbon dioxide and other constituents of air, "these gases, particularlythe oxygen are present in suflicient quantity to produce a corrosiveaction upon the metal of the boiler, and other apparatus included in thesystem, at high temperature operation. The extent of this corrosiveaction has led in recent years to the more or less general inclusion ofdeaerating apparatus in steam power systems so as to supply substantially gas-free Water to that apparatus of the 1 system which operatesat high temperature.

Deaeration of the Water is accomplished by passing it into a suitable-vessel and heating to the temperature corresponding to the pressureWithin the vessel. Deaeration may he carried on at almost any desiredtemperature and pressure. 'lhus deaerating apparatus may be operated atpressuresfar below atmospheric, at atmospheric pressure, and atpressures considerably above atmospheric pressure. It has been founddesirable, however, to carry on the deaeration at comparatively hightemperatures because at such temperatures the Water has less afinity forthe gases and they are therefore more readily separated.

'hurthermofre, in the study of the problem of .deaeration it has beenfound advantageous to'treat the water in two zones. ln th'e' first zoneof treatment substantially complete deaeration is effected by contactheating of the Water With steam in suiiicient quantity and at suchtemperature as to produce the desired temperature of the Water. lln thesec- 0nd zone of treatment the Water is subjected to a temperaturehigher than that of the steam supply for the first zone and higher than"the final temperature of the completely in. teaser.

deaerated "Water. lhe action of this second none of treatment is toprevent the enrichmerit of the Water with air or gas from the vapor inthe first zone, and also to carry the deaeration further on, providing asort of secondary deaerating efiect.

lhe apparatus'for carrying out deaeration in this way comprises anelongated vertical chamber into which the Water to be deaerated issupplied at the top. Steam or vapor at appropriate temperature isintroduced into 7 contact with the Water Within the chamber, and tobring the Water and steam into more intimate contact means such as traysor baffles are usually provided Within the chamber for finely dividingthe Water into drops or rain so that the largest possible surface ofWater will be presented to the action of the steam, thus efifectingrapid heating of the Water and condensation of the steam.'

The Water Which has been heated through this exchange of heat, and thecondensed steam, collect and form a body of liquid in the lower part ofthe chamber. Submerged in this body of liquid is a bubble pipe or a 7surface heat transfer means, such for example as a tube bundle, andthrough one or the other of these instrumentalities steam at a highertemperature is supplied to efiect the treatment in the second zonementioned above. Instead of being submerged in the body of Water at thebottomof the chambclaim; the tube'bundle may be placed just above theliquid level, and the rain or spray of Water will descend from the upperpart of the chamber onto and through this tube bundle and collect at thebottom of the chamber. The spray tends to form films of liquid on thesurfaces of the tubes but Whenthe spray strikes these hot tubes aviolent ebullition of the liquid in the film form is produced and aportion of the liquid is vaporized. This violent vaporization of aportion of the liquid, I and the vapor resulting therefrom produces thefinal or secondary deaeration effect, removing the last remainingparticles of air and other non-condensible gases. This Will be referredto herein as the unsubmerged tube bundle type of deaerator.

When the bubble pipe or submerged tube bundle is used ebullition andagitation of the body of liquid result and a moderate amount of vapor isreleased. All three of these actions, namely, the action of thesubmerged bubble pipe, the action of the submerged heat transfer means,and the action of the unsubmerged heat transfer means, serve to carryfurther on the deaeration which has been produced by the contactheating. In all three of these types of deaerators the outlet for thenoncondensable gases isat the top of the rain chamber, and the vaporproduced by the secondary deaerating effect joins the contact heatingsteam entering at the lower part of the rain chamber and the mixture ofvapor and steam rises in the rain chamber in the opposite direction tothe downward flow of the water undergoing deaeration. This counterflowof vapor carries with it the air andother noncondensable gases towardthe outlet at the top.

The problem is to fit the deaerating apparatusinto various steam powersystems with as little disturbance or change in the layout of theparticular system as possible.

The diiiiculty encountered in attempting to introduce a deaeratingapparatus into a steam power system is caused by the fact that the steamto be supplied to the bubble pipe, or to the submerged tube bundle, orto the tube bundle placed above the surface of the liquid mustbe at ahigher temperature than the steam conducted into the rain chamber orshell of the apparatus for contact heating. This latter steam may becalled the primary or principal heating steam whereas the former steam,that is, the steam for the bubble pipe or tube bundles may be termed thesecondary heating or secondary deaerating steam. It has been found byinvestigation that the secondary heating steam may advantageously befrom about 2 F. to about 20 F. higher in temperature than thetemperature of the principal heating steam for deaerators employing thebubble pi e type. With deaerators of the tube bun le type, whetheremploying a tube bundle above or below the liquid level, investigationhas shown that the secondary steam should be in the neighborhood of 10F. to 30 F. above that of the primary heating steam.

It has been customary heretofore to supply both the primary and thesecondary steam from the same source, such for example as the vaporoutput of an evaporator. With this arrangement, although the amount ofprimary heat consumed in deaerating apparatus is far in excess of thatof the secondary heat, the usual proportions being about to primaryheat, and 5 to 15% secondary heat, nevertheless the evaporator is steamplant operating a 50,000 k. w. turbine, the amount of primary steamcondensed in the deaeratin apparatus would perhaps be in theneighborhood of 20,000 to 30,000 pounds per hour, so that themaintaining of this amount of vapor or steam at say 10 to 25 highertemperature than necessary is an important consideration, necessitatingthe installation of an evaporator of much larger capacity than would berequired if deaeration were not included in the system. In other words,the furnishing of the total quantity of steam required for deaerationprocesses at the maximum temperature which is determined by thatnecessary for the secondary steam subjects the source of deaerator steamto a penalty which is very likely to necessitate an undesiredmodification in other apparatus of the steam power system in order toaccommodate the deaerating apparatus.

Accordingly the principal object of the present invention is to soassociate av dcaerating apparatus with a steam power system that themost economical kind or quality of steam may be consumed in thedeaerator.

A further consideration is that of the large variety of steam powersystems which are required to meet varying local or desired conditionsin the output of the system. Some systems, for example, utilize steamfor industrial uses which steam is not returned to the system, andconsequently a large evaporator capacity must be installed in order totake care of the relatively large feed water make-up. In such a systemit is necesary to return the heat of the evaporator vapor to the systemand this may conveniently be done by means of the deaerating apparatus.In other steam powersystems the amount of boiler feed make-up may berelatively small because little or no steam is taken from the systemexcept by leakage and/or because the available supply of boiler feedwater is relatively pure and uncontaminated. In systems of thisvkind theevaporator capacity would be comparatively small and it would then benecessary to revise the scheme for supplying heat to the deaeratingapparatus,

and inthis case it might be found advantames es may be used with steampowersystems in ac cordance with the invention. These draw- I ings areall diagrammatic. In these drawpower system showing a deaerator of the.

gubble type receiving steam bled from a turme; I

Fig. 2 is a similar view showing a deaerator of. the unsubmerged tubebundle type con nected to a bleeder turbine;

Fig. 3 is a view showing a deaerator like that of Fig. 1 receiving heatfrom an evaporator andfeed water heater;

Fig. 4: shows a deaerator of the type illustrated in Figs. 1 and 3 withthe bubble pipe replaced by a submerged heating coil or tube bundle, thedeaerator receiving its heat from an evaporator;

Fig. 5 shows an unsubmerged tube type deaerator supplied with heat'fromtwo separate evaporators; and

Fig. 6 shows acomplete steam power system except for the boilerincluding a de a'eratorand bleeder feed water heaters.

Referring now-to the accompanying drawings and particularly to Fig. 1,the deaeratoi here shown comprises a'shell 10 into which.

the water to be deaerated is admitted through a pipe 11. The waterentering through pipe 11 at the top of the deaerator descends throughthe upper portion of the shell 10 which forms a rain chamber 12 andcollects in a body of liquid 13 at the bottom of the shell. Any form oftrays, battles or other distributing means may be provided within theshell 10 to cause the water to be finely subdivided as it traverses therain chamber. The oxygen, air and other non-condensible gases arewithdrawn from the deaerator through the outlet pipe 14: by any suitablemeans (not shown). The completely deaerated water is withdrawn from theapparatus at the bottom through pipe 15- by means of a feed pump 16 andmay be passed through a feed heater 17 and thence through pipe 18 to theboiler or other appropriate part of the system. Y

A The system includes a turbine 19 which receives steam through pipe 20and which is provided with an exhaust pipe 21. The primary or principalsource of heat For the deaerator 10 consists of steam which is bled fromone of the lower stages of the turbine through pipe 22 at a relativelylow temperature and pressure, the positionv of the bleeder stage beingchosen to give steam at the desired "temperature. This steam enters therain chamber 12 at the point 23 just above the liquid level and servesto heat thewater as it descends in finely divided form through the rainchamber. As the steam contacts with the falling water it condenses andis added to-the body of water 13. The bubble pipe 24 consists of a pipepositioned near the bottom of the shell 10 having perforations in itssurface so as to allow steam to be ejected through these perforationsdirectly into the body of liquid. This bubble pipe is supplied withsteam through a connection 2'5 from a difierent stage of the turbine 19where the steam is at a higher temperature than that supplied by thepipe 22.

' The heating of the water in the rain chamber by means of the principalheating steam entering at 23 causes the air and othergases to bereleased from occlusion in ,the water to such an extent that the waterin the body of water 13 is substantially completely deaerated. The steamdischarged through the apertures oi the bubble pipe 24E causes a violentagitation or ebullition of the body of liquid 13 both on account of thevelocity with which is emerges through the apertures and also because ofthe additional heat which it imparts. This agitation and further boiling of the liquid prevents the enrichment thereof with gases by contactof the body of liquid'with the vapor and gases in the rain chamber. 1tfurthermore carries the deaeration a little farther. or addsa final de-I aeration kick before the deaerated liquid is withdrawn through thepipe 15.

The total quantity of steam'bled from the turbine through pipes 22 and25 is so proportioned by means of valves (not shown) to the amount ofwater entering the d'eaerator through pipe 11 as to produce atemperature of the mixture which is the same as that of the primarysteam supplied through pipe 22, but by tar the greater amount of steamcomes through the primary supply pipe 22 from the 'low pressure lowtemperature source,name-t ly the lower stage of the turbine where thegreater part of the energy in the steam has been extracted by theturbine in doing mechanical work. Thus according to the invention theprincitea its

pal heating steam for the deaerating appara- T tus is taken from arelatively low temperature source of supply in relatively largequantity, and the secondary heating steam is taken from a relativelyhigh temperature source of sup-Q ply in relatively small quantity. Thisper higher stage of the turbine where the pipe 25 1 is connected, inorder to provide the desired temperature for final deaeration.

Referring now to Fig. 2 of, the" accompanying drawings, the arrangementshown here is similar to that shown in Fig. 1 aside from the type ofdeaerator employed. This form of deaerator comprises a shell 26 having acomparatively large tube bundle 27 arranged at its lower part but abovethe level of the body lated by varying-the of liquid 28. The principalheating steam enters at the point 29 fromthe lower stage of the turbineand heats the Water in therain chamber by direct contact therewith asabove described in connection with Fig. 1.

evolved comminglcs and coacts with the primary source of steam in itscontacting with and heating of the falling Water in the rain chamber.

Condensate from tube bundle 27 passes into a trap 30 and thence throughpipe 31 it is led into the rain chamber where it assists to some slightextent in heating the liquid, and is itself subjected to deaeration.

lVith this type of deaerator the advantages arising from the presentinvention aresome- What greater than with the type of deaerator shown inFig. 1 since with this form of deaerator the secondary steam will besupplied at a greater difference in temperature from the primary steam.

In Fig. 3 of the drawings a deaerator like that shown in Fig. 1 isfurnished with steam from two sources of supply at differenttemperatures in a somewhat different manner. Here the primary heating'means for the deaerator which is led into the rain chamber at point 23is the vapor from an evaporator 32. The heating coils of this evaporatorare supplied with steam at any suitable higher temperature and pressurethrough a pipe 33 from any suitable source. The water supply to theevaporator enters through pipe 34-. The evaporator coil drains pass intoa trap 35 and thence through a pipe 36 to the bubble pipe 24 of thedeaerator.

If it is desired, the feed heater l7 may be supplied with steam througha pipe 37 from the same source as that which feeds evaporator 32. Thecoil drains from this feed heater, after passing through a trap 38, maybe led through a pipe 39 to join the coil drains in pipe 36 from theevaporator.

, WVhen the 'deaerating apparatus is suppl'ed with separate sources ofheating steam de rived from an evaporator in accordance with thenventlon I have ust described, the-temperature of the principal heatingsteam supplied from the evaporator shell may be reguamount of steam fedto the evaporator through valve 40. The saturated temperature of thesteam in the heatsupply line, so that at all times ing chamber, i. e.the coils of the evaporator will usually be 35 to 45 Fvhigher than theevaporator shell pressure and the temperature corresponding to thepressure in the deaerator shell so that the contained heat in the drainsfrom the evaporator heating chamber will on entering the collected water13 in the deaerator'impart an appreciable amount of heat which in theform of flash will cause considerable agitation. The heating drains fromheater 17 will act in a similar manner. There will preferably be nocontrol valve in evaporator vapor line 23 because the evaporatorcapacity may be entirely con.- trolled by valve 40 in the evaporatorheat the pressure and temperature of the evaporator vapor will exactlycorrespond with the pressure in the deaerator. For this reason therewill be no lessening of the preferred operating temperadeaerator. If,however, the steam from the vapor space of the evaporator were sent bothinto the deaerator shell and into the bubble pipe, it would be necessaryto operate the evaporator at a higher temperature in order to providethe desired action of the superior temperature of the bubble pipe. Thiswould necessitate that the evaporator produce all of its vapor at ahigher temperature, and, particularly when the tube bundle typedeaerator is employed in place of a bubble pipe deaerator, requiring 10to 30 F. higher temperature for the secondary steam the size of theevaporator would have to be materially increased.

In Fig. 4 a third type of deaerator has been illustrated. This deaeratoroperates in a manner quite similar to the bubble type of apparatus shownin Figs. 1 and 3, the main difference being that the secondary heatingsteam transfers its heat to the body of liq- .uid in the bottom of thedeaerator through a surface transfer means such as a relatively smalltube bundle, the condensate from this tube bundle being returned to therain chamber of the deaerator.

This deaerator also comprises a shell having a rain chamber 41 atitsupper portion and a secondary deaeration zone at its lower portionwithin which is the body of liquid 42. Submerged in this liquid is arelatively small tube bundle 43. The water to be deaerated enters asbefore at the top through the pipe 11 and the non-condensible gases arewithdrawn through pipe 14. Also the deaerated water is withdrawn at thebottomv through pipe 15 by means of pump 16.

The principal heating means is supplied through pipe 44 from the vaporspace of an evaporator 45 as in the ease of Fig. 3, the

intense I evaporator being supplied with Water through pipe 46.Relatively high temperature heating steam for the evaporator 45 entubesto the collected water. lit the full temperature of the evaporatorheating steam is desired in the tube bundle the trap 48 may be omittedand valve 53 may be omitted and a suitably positioned trap may beincorporated in line 51.

In operation the steam from the evaporator shell heats the incomingliquid in the rain chamber 41 by direct contact as in the case of thedeaerators previously described,

suitable trays or baflles being provided for distributing the water in afinely divided spray. The heated and deaerated water collects in a body42 at the bottom, and is given a secondary deaeration by means of thetube bundle 43. In this'case the mechanical agitation of the liquid inthe body of liquid 42 which is produced by the velocity ofthe steamadmitted by the bubble pipe in the. deaerators of ]Figs. 1 and 3 isabsent. However, suitiof the liquid 42 by heat transferred through the.tube bundle. This secondary heatingthus prevents enrichment offtheliquid with gas-as before, and provides a finishing step of 'deaeration.

Again the slze of the evaporator does not have to be increased in orderto accom- I modate the deaerator in the system as would bethe case ifthe steam both for contact heating and for the secondary heating wereboth supplied by the vapor from the evaporator, instead of being takenfrom independent sources of differenttemperature.

ln many steam power systems a'plurality 0t evaporators are includedinstead of merevly a single evaporatonand deaerating ap-- paratus can bereadily associated with such.

a system in accordance with my invention. Ordinarily in such avsystemthe lines from the vapor. spaces of all of the evaporators .ozt'theplant would be joined together and 'connected both to the deaeratorshelland tubes or bubble pipe. This necessitates that all of theevaporators be operated at a higher temperature than necessary in orderto supply heat at the heat level required by the tubes or bubble pipeor, in other words, by the secondary heating. This required higher vaporpressure of evaporator's not only in general greatly increasestheexpense of the necessary transfer surface but at times makes itnecessary to heatthe evaporators by steam "from a still higherextraction point of the turbine which causes a significant'power decinaccordance with theinvention whereby the ill principal heating means forthe deaerator is supplied by the vapor from one evaporator, and thesecondary heating means is supplied by the vapor from the otherevaporator. The

deaerator here is similar to the one described in connection with Fig.2, therwater entering at the top through pipe 11 and descending through.a rain chamber where it is brought into contact with the principalheating means.

Descending further, the -water and condense'd steam or vapor strike thetubes of tube bundle 27 which are maintained. at a higher temperature,say for example some 12 above the temperature of the rain chamber. Anintense ebullition of the films of liquid on the tubes is thuspro'ducedas previously described in connection with Fig 2,

andthis filming ebullition and consequent,

evaporation of a portion of the water as "it traverses the tube bundleproduces the secondary or .final deaeration. The vapor pro duced bythetubes 27 also forms a rising blanket of relatively clear vapor, that is,

rain chamber at the point 29through pipe "vapor free from gas above thebody of liquid 7 p 28 which prevents the enrichment of this cientagitation is produced by the ebullition 54 which leads from the vaporspace of an evaporator 55. The higher temperaturesteam or vapor for thetubes 27, that is, for the secondary heating, is fed through a pipe 56from the vapor space of a second evaporas tor 57. The evaporator coils58. and 59 may receive their steam through a common supply pipe 60 fromany suitable source of steam at an appropriate temperature." The drainsfrom these coils are led-back into the boiler teed supply system at anyconvenient point. Water is supplied to the evaporators 55 and 5'3through the pipes 61 and 62' The condensate from tube bundle 27 isconducted into the rain .chamber of the deaerator through trap 30 andpipe 31.

ln the usual installation of steam power systems the vapor spaces of allthe evaporators are joined together and arranged-to teed both theprimary and secondary heating means of the deaerator so that all of theevapltd orators are subjected to the temperature I hardship ofbeingoperated to produce heating steam tor the deacrator at the highertemperature requirements of the secondary heatrat ing means. However, byconnecting the evap orators and deaerator in accordance with are presentinvention only evaporator-'57 need be ltd operated at the highertemperature. In the usual installation of the invention evaporator 57need be but about one-quarter the size of evaporator 55 so that themajor portion of the evaporator system may be operated at the lowertemperature, and the temperature hardship is imposed upon only acomparatively small part of the system.

In present day practice in the installation of steam power systems ithas been found extremely advantageous to heat the feed water to withinsubstantially 75 to 100 of the vaporization temperature corresponding tothe pressure at which the boiler of the system is operated beforeallowing the water to enter the boiler. This heating of the boiler feedwater can be most economically accomplished in a plurality of separateheaters through which the feed water passes successively, the waterthereby being heated in steps to successively higher heat levels ortemperatures, instead of being heated to the final temperature at oneoperation'in a single heater. In this way steam at different suitabletemperatures for the individual feed heaters can be taken from differentstages of the turbine after a portion of its energy has been removed indoing useful mechanical work in the turbine.

In associating a deaerating apparatus with such a system it must be donein such a way as not to interfere with the desired operation of theturbine, feed heaters and'other a pparatus of the system and "in Fig. 6of, the accompanyin drawings I have shown a deaerator of theunsubme-rged tube type fitted in between. the intermediate and hightemperature feed heaters.

The turbine 63 receives its steam from the boiler (not shown) through asupply pipe 64:. The exhaust from the turbine is led through a conduit65 to the usual condenser 66 and the condensate is withdrawn from thecondenser through pipe 67 by means of a boiler feed pump 68 anddelivered through a pipe 69 to the first stage or low temperature feedheater 70.

Feed heater 70issupplied with low pressure, low temperature steamthrough a pipe 71 which leads from a low pressure stage of turbine 63.The feed water, which enters this heater at about 85 F. is thereforeraised in temperature to in the neighborhood of per-' haps 140 F. atwhich temperature it leaves feed heater 70 through connection 72 andeinters the next or intermediate stage heater Heater 73 is suppliedwithsteam through a pipe 74:, from an intermediate stage of the turbinewhere the pressure is for example, around 23 pounds absolute. Thetemperature corresponding to this pressure is 235 F. and

the water therefore might issue from heater 73 at about 230 F. =Thewater thus heated,

is carried through line 75 to the top of the deaerator 76 which isprovided with a rain chamber 77 and a tube bundle 78 above the liquidlevel of the body of liquid 79. The condensate from heater 73 afterpassing trap 101 is conveyed through line 102 to the shell of the firststage heater 70 where it contributes to the temperature rise of the feedwater entering this heater through line 69.

Continuing our assumed figures, a desirable rise in temperature indeaerator 76 would raise the temperature of the deaerated water toaround 270 F., and this water is led through line 80 to the third stagefeed heater 81.

Third stage heater 81 receives steam through line 82 from a relativelyhigh pressure stage of turbine 63. Assuming that this stage pressure is121 pounds absolute, the

saturated temperature corresponding thereto is about 34:2" F. and heater81 will therefore heat the feed water to about 336 F. at which I it isfed through pipe 83 to the boiler.

In associating the deaerator 76 with a stage heating system inaccordance with my invention, an evaporator 84 is provided, the coils 85of which receive the steam through a pipe 86 from line 82 and hence fromthe same source as feed heater 81. The vapor space of evaporator 84 isjoinedthrough line 87 with the rain chamber 77 of the deaerator and theprincipal heating means is therefore supplied" by the evaporator vapor.The amount of steam delivered to the evaporator coils will be regulatedin accordance with the percentage of make-up required. Thetem peratureofthe evaporator vapor and the temperature of the deaerated water will atall times be substantially equal. Water for the evaporator 84 issupplied through pipe 88 and it is in this way that the boiler feedmakeup is addedto the boiler supply.

The condensate or drains from the coils 85 which are at a relativelyhigh temperature with respect to the evaporator vapor are led through atrap 89 and line 90 to a flash tank 91. The drains from feed heater 81may.'if

desired, also be led through trap 92 and line 93 to the same flash tank91 so that their heat is added to the heat of the drains from evaporator84. The vapor space of the flash tank respect to the flash tank 91 thatthe temperature of the flash tank will be maintained at about 285 F., orsome 15 higher than the rain chamber and outlet of the deaerator. Thevapor passing through pipe 94 into the maaoaa tube bundle is thereforeat the right tem- .perature to effect appropriate secondary deaerationby means of the tube bundle. The hot'water which does not flash to steamin the flash tank is conducted through pipe 97 and is added to the waterin the rain chamber wherein itis subject to deaeration.

By this arrangement pf the apparatus the principal heating means for thedeaerator 76 comes from thevapor space of evaporator 84 which mayconveniently be operated at the proper temperature to produce thedesired rise in temperature of the feed water as it passes through thedeaerator. Inasmuch as 15 the drains from evaporator 84: and heater 8].are eventually added to the body of liquid 79 they contribute to acertain extent in raising the temperature of this liquid. The rel ativequantities of heat furnished by the coil 23 drains andby the evaporatorvapor ar-e such,

howeventhat the coil drains produce a relatively small proportion of thetemperature rise. Thus, for example the total'rise in temperaturebetween the point where the water 35 enters the top of the deaerator andthe pointwhere it leaves the deaerator is'in the "ex-j ample given 40",and of this temperature rise about 34 is supplied by the evaporatorvapor, about 2- by the evaporator coil drains, and

30 about 4 by the heater drains.

Theisecondary heating means aeratingapparatus is .supplied by the flashfrom high temperature drains at the appro-' priate temperature toproduce the most effi- 35 cient operation of'the deaerator and yet nopenalty in the form of increased temperature of operation of theevaporator, or increased size' of the evaporator, is placed upon thepower system.

It- .common practice were resorted to the high temperature drains wouldbe passed directly into therein chamber.v It then the shocking (i. e.secondary) deaeration were undertaken by vapor from the evaporator the4.3 evaporator vapor would have to be maintained at a pressurecorresponding to say 15 higher temperature which would necessitate aconsiderably larger evaporator. Furthermore, there would have to be areducing valve :3 or other control in the vapor line supplying theprincipal heating means so that the proper temperature relationwould bepresent in the tubes in order to eflect transfer therefrom.

I claim:

l... lln a steam power system, a deaerating apparatus having a primaryheating means and a secondary heating means, an evaporator having itsvapor space arranged to deliver. f3 steam to said primarylheating means,a flash tank, means for conducting the drains from the evaporatorheating chamber to said tank, and means for conducting the vapor fromsaid. sflash tank to said secondary heating 55 means'o'lt thedeaeratingapparatus. 1

2. lln a steam power system, a deaerating apparatus having a primaryheating means and a secondary heating means, an evaporator having itsvapor space connected to supply steam to said primary heating means, aflash tank, means for conducting the drains from the heating chambcrpfthe evaporator to said tank, means for delivering the vapor fromsaidtankito said secondary heating means.

and means for delivering the water from said flash tank to thedeaerating apparatus.

- i 3. In a steam power system including'an evaporator and a feed waterheater, a deaera-ting apparatus having a primary heating means and asecondary heating means. means for conveying the vapor from theevaporator to said primary heating means, a flash tank, means forconveying the drains from the heating chamber of said evaporator andfeed heater to'said flash tank, and means for conducting vapor from saidtank to said second ary heating means.

i 4:- In a steam power system the combination of a 'turbin-e,'aplurality of successive feed Water heaters deriving heating steam atappropriate temperatures from various stages of said turbine, adeaerator arranged to receive water from one of said feed heaters'anddeliver it to the next higher temperat-ure'.1 feed heater, saiddeaerator having a i for the des primary heating means. and a secondaryheating means, an evaporator supplied with steam from the same stage ofthe turbine as said higher temperature feed heater, means, for

conducting steam from the vapor space of said evaporator to said primaryheating means, and means for'conveying heat of the drains from saidevaporator heating chamber to said secondary heating means.

5. In a steam power system the combina tion of a turbine, a plurality ofsuccessive feed water heaters deriving heating steam at appropriatetemperatures from various stages of said turbine, a deaerator arrangedto receive water from one of said feed heaters and deliver it to thenext higher temperature feed heater, said deaerator having a primaryheating means and a secondary heating means, an evaporator supplied withsteam from the same stage of the turbine as said higher temperature feedheater, means for conducting steam from the vapor space of saidevaporator to said primary heating means, a flash tank, means for conteying the drains from the heating chamber of said et'ap'oratoimto saidflash tank, means for.conducting the vapor trom said tank to saidsecondary heating means, and means i or directing the'water from saidtank into said boiler feed system.

6. in a steam power system including an evaporator and a teed waterheater, receiving heating steam at substantially the same temperature asthe evaporator, a deaerating apparatus having a primary heating meansand a secondary heating means, means for means for supplying heatingsteam to said feed water heater and to said evaporator,

1 means for conveying the vapor from the evaporator to said primaryheating means, a flash tank, means for conveying theldrains from theheating chamber of said evaporator to said flash tank, and means forconducting vapor from said tank to said secondary heating means.

8. In a steam power system the combination of a boiler feed systemincluding a plurality of successive feed water heaters deriving heatingsteam at appropriate temperatures from various stages of said turbine, a

- deaerator arranged to receive water from said primary I conveyiug heatof the drains from said'evaporator"heating chamber to said secondary I;

' tion of a turbine,

said system and deliver it to one of said feed heaters, said deaeratorhaving a primary heating means and a secondary heating.

means, an evaporator supplied with steam from said primary heatingmeans, and means for conveying heat of the drains from saidevaporatorheating chamber to said secondary heating means. 9. In a steam powersystem the combination of a turbine, a boiler feed system including aplurality of successive feed water heaters deriving heating steam atappropriate temperatures from various stages of said turbine, adeaerator arranged to receive water from said system and toreturn itthereto after deaeration, said deaerator having a primary heating meansand a secondary heating means, an evaporator supplied with steam fromthe same which supplies heating steam to one of said feed'heaters, meansfor conducting steam from the vapor space of said evaporator to heatingmeans,'and means for stage of the turbine heating means. I

10. In a steam power system the combinaa boiler feed heating systemincluding a plurality of successive feed water heaters deriving heatingsteam at appropriate temperatures from various stages of said turb ine,a deaerator arranged to receive water from one of said heaters anddeliver it to said boilerfeed system, said deaerator having a primaryheating means and a secondary heating means, an evaporator power systemincluding an the same stage of the turbine as said feed heater, meansfor conducting steam from the vapor space of said evaporator to.

supplied with steam from a stage of said turbine, means for conductingsteam from the vapor space of said evaporator to said pri- -mary heatingmeans, and means for conveying heat of the drains from said evaporatorheating chamber to said secondary heating means.

11. In a steam power system the combination of a turbine, a boiler feedheating system including a plurality of successive feed water heatersderiving heating steam at appropriate temperatures from various stagesof said turbine, a deaerator arranged to receive water from said systemand to deliver it to one of said feed heaters, said deaerator having aprimary heating means and a secondary heating means, an evaporatorsupplied with steam at substantially the same temperature as the heatingsteam for said feed heater, means for conducting steam from the vaporspace of said evaporator at said primary heating means, and means forconveying heat of the drains from said evaporator heating chamber tosaid secondary heating means. I

In testimony whereof I aflix my signature.

STANLEY BROWN .1

